Forest(Continued)

Mangrove forest
-The structure of the forest
A mangrove forest has three distinctive zones. Mangrove tree vary in height from 2m to 40m as the muddy soil in the coastal environment cannot provide firm support for tall trees to grow. At an average height of 15m, mangrove trees are generally shorter than the trees in tropical rainforests.

3 distinct horizontal zones of mangrove species:
- Coastal zone
Trees along the coast have adapted to growing in salt water, as the coastal zone is flooded with seawater during high tide. The trees have breathing roots or aerial roots.

- Middle zone
They have prop roots or stilt roots.

- Inland zone
Bruguiera trees grow further inland, as they are the least tolerate of salt water. They have knee-like roots.

Types of roots:
- Aerial roots
The aerial roots of Sonneratia are exposed during low tide. It allows them to take in oxygen.
- Prop roots
The prop roots of the Rhizhopora provide support for the trees on muddy soil.
- Kneed roots
The kneed roots of the Bruguiera resemble bent knees.

Coniferous forest
Structure of the forest
The coniferous forest has no layers. The trees in the coniferous forest grow tall and are generally uniform in height, around 20m to 30m. The trees also grow close together. There is little undergrowth in the coniferous forest. This is due to the low amount of sunlight received in the temperate region and the low soil nutrient level caused by the nature of the leaf litter is made up of tough needles, which do not break down easily to supply nutrient to the soil.